Motor-driven conveying rollers of the kind mentioned in the introductory part are used in numerous applications in order to convey objects such as containers, pallets, packages, items of luggage and the like. In this case, conveying rollers of this kind are used as roller drives in which the conveying line is formed by a plurality of conveying rollers which are lined up with one another and of which some are motor-operated and others are formed as idling rollers or are driven by motor-operated conveying rollers by way of belt drives or the like. Motor-operated conveying rollers can further be used as so-called drum motors in order to drive, for example, conveyor belts and for this purpose are installed as deflection rollers on one side for example.
Motor-operated conveying rollers of this kind generally have a drive motor which is arranged within the roller body, is electrically operated, and generates a torque between an axle element and a roller body. Typically, the axle element is fastened in a rack fixedly in terms of torque, and the roller body is set in rotation relative to the axle element by the torque. Here, energy is supplied to the drive motor by an electrical connection which is routed through the axle element. For this purpose, the axle element is formed as a hollow axle, so that a cable line can be laid through the axle element from the outside and can be connected to the drive motor.
In order to be able to easily replace a motor-operated conveying roller, it is known to design said electrical power supply in such a way that it can be disconnected using simple means. As a result, firstly when the motor-operated conveying roller is defective, the conveying roller can be exchanged without a great deal of expenditure in respect of the electrical connection by way of the electrical power supply being disconnected and then, after removal of the defective conveying roller and installation of a conveying roller which is in working order, said electrical power supply being correspondingly connected again. Secondly, in the event of damage to the electrical power supply, for example, if a cable is accidentally damaged or severed, said cable can be replaced in a simple manner without removal of the conveying roller being necessary for this purpose.
EP 2 161 223 already discloses a releasable electrical plug-in connection of this kind in which a plug is inserted into a socket which is arranged in the cavity in the axle element. Here, for securing purposes, the plug is either screwed to the axle element by means of a union sleeve, which is axially fixed to the plug, or secured to the axle element by means of a latching pin connection which is formed on the plug. Although the electrical plug-in connection can be released in a simple and rapid manner with this design, it has been found, firstly, that an ability to release said connection in this way, with this design has disadvantages. Firstly, the plug-in connection can be released in a simple manner, this possibly leading to erroneous installation processes due to the actions of unauthorized and inadequately trained personnel. Secondly, owing to the screw- or pin-secured connection, it is possible for liquid to pass from the surrounding area into the interior space in the roller body and into the region of the electrical plug-in connection itself. This makes it impossible to use a conveying roller which is formed in this way in regions which are exposed to moisture and, in particular, splashing water, such as in sectors of the food-processing industry in which frequent cleaning of the conveying line is necessary, for example.
For applications of this kind and for preventing mounting faults, it is known to realize an electrical terminal connection by means of a sealed-off mounting box which is installed directly on the motor-operated conveying roller or on the rack adjacent to the motor-operated conveying roller. In this case, sealed-off boxes can be used, and a design which is protected against splashing water in this respect can be achieved. However, this has the disadvantages of additional expenditure on mounting and additional space requirement in order to realize this way of mounting in a manner sealed off from splashing water. Therefore, permanent electrical supply lines are still often used in regions of the conveying lines of food-processing installations in order to supply power to motor-operated conveying rollers and/or to pass signals and/or data from sensors, such as encoders or thermal circuit breakers for example, to the outside, this having the above-described disadvantages when it is necessary to replace the conveying roller or the line cable due to damage.
The invention is based on the object of providing a motor-operated conveying roller which, in regions which are exposed to splashing water, has a more suitable electrical power supply and, in the process, improved properties in respect of mounting in comparison to the prior art.